Ms Cahill, who was raped by a senior IRA figure before being subjected to a kangaroo court, is widely expected to win the by-election in November.

The Belfast woman is due to visit Leinster House today where she will meet senior Labour figures to discuss election strategy.

She agreed to run for the party after being contacted by Labour deputy leader and Environment Minister Alan Kelly.

The by-election was prompted by the retirement of respected Donegal senator Jimmy Harte, who has suffered from poor health in recent months.

Mr Costello, a TD for Dublin Central, has been appointed director of elections.

Labour TD Joe Costello

Sinn Féin and Fianna Fáil are both considering running candidates opposing Ms Cahill, who shot to prominence after speaking about being abused by the IRA and the subsequent cover-up by members of the republican movement.